Macro expansion results in a constant boolean expression

[pauluap]

Description

In file included from .././features/FEATURE_LWIP/lwip-interface/lwip/src/include/lwip/ip_addr.h:43:0,
                 from .././features/FEATURE_LWIP/lwip-interface/lwip/src/include/lwip/netif.h:46,
                 from ../features/FEATURE_LWIP/lwip-interface/lwip_stack.h:23,
                 from ../features/FEATURE_LWIP/lwip-interface/lwip_stack.c:23:
../features/FEATURE_LWIP/lwip-interface/lwip_stack.c: In function 'mbed_lwip_socket_bind':
.././features/FEATURE_LWIP/lwip-interface/lwip/src/include/lwip/ip4_addr.h:171:40: warning: the comparison will always evaluate as 'false' for the address of 'ip_addr' will never be NULL [-Waddress]
 #define ip4_addr_isany(addr1) ((addr1) == NULL || ip4_addr_isany_val(*(addr1)))
                                        ^
.././features/FEATURE_LWIP/lwip-interface/lwip/src/include/lwip/ip_addr.h:272:49: note: in expansion of macro 'ip4_addr_isany'
 #define ip_addr_isany(ipaddr)                   ip4_addr_isany(ipaddr)
                                                 ^~~~~~~~~~~~~~
../features/FEATURE_LWIP/lwip-interface/lwip_stack.c:1138:10: note: in expansion of macro 'ip_addr_isany'
     if (!ip_addr_isany(&ip_addr) && !mbed_lwip_is_local_addr(&ip_addr)) {
          ^~~~~~~~~~~~~

Because the function ip_addr_isany() is actually a macro, it ends up being expanded in place with a constant boolean result.

My solution is a dirty trick, providing a pointer variable alias. My thought that is the ideal solution would use a function rather than a macro, but there's probably other considerations

Pull request type

[X] Fix
[ ] Refactor
[ ] New target
[ ] Feature
[ ] Breaking change

[kjbracey]

I think the correct and optimised fix is to use ipaddr_is_any_val(ip_addr). Can you try that?

[pauluap]

Yes, replacing with ip_addr_isany_val is still successful in suppression of the compiler warnings

[kjbracey]

Fine, but please squash to one commit and get rid of all the unconnected formatting changes. We've got a big merge coming in from feature-emac, and I want to minimise conflicting changes to these areas.

[pauluap]

Cool. Done.

[cmonr]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 1748
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/6613/

Triggering tests

/morph test
/morph uvisor-test
/morph export-build
/morph mbed2-build

[mbed-ci]

Exporter Build : SUCCESS

Build number : 1383
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/6613/

[mbed-ci]

Test : SUCCESS

Build number : 1551
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/6613/1551

[0xc0170]

/morph mbed2-build